NICI > Publications > 1997 > Assimilation: Central and peripheral effects
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Reference
De Weert, C.M.M., & Van Kruysbergen, A.W.H. (1997). Assimilation: Central and peripheral effects. Perception, 26 (10), 1217-1224.
Abstract
Assimilation and contrast have opposite effects: Contrast leads to an increase of perceived differences, whereas assimilation leads to a reduction. It is relatively easy to demonstrate these effects, but the precise localisation of these effects in the perceptual system is not yet possible. Contrast and assimilation not only depend on peripherally located mechanisms, but also on central mechanisms. In an experiment the strength of assimilation effects was modified by adding spatial noise. By varying the localisation in perceived space of the added noise (by presentation of the noise pattern with different binocular disparities) the masking effect of this noise can be influenced. Binocularly disparate noise causes less masking than binocularly non-disparate noise. Our conclusion is that the effect at least partly occurs beyond the (binocular) locus of separation in different depth planes. A similar approach, involving moving noise, will also be presented. Finally, several demonstrations show that peripherally similar images can give rise to differences in the perceived amount of assimilation. These effects also indicate that a central mechanism is involved in assimilation.